Meet six young horticulturists who are helping to shape how America gardens.

Toward the end of the 20th century, horticultural trailblazers introduced remarkable plants, took risks with design, and presented innovative techniques. The success of these public and private garden makers, nurserymen, plant explorers, and writers made them well known and well regarded, even famous.

Fast-forward to today: Who are some of the young professionals who will have an impact on gardening in the years to come? These people are not yet celebrities, but that may just be a matter of time. We looked for some of the next-generation stars of horticulture to discover their philosophies and what they see for the future of gardening in America.

The Hybridizer: Joseph Tychonievich

A few years ago, Lynne Rosetto Kasper, the host of the public radio cooking show The Splendid Table, complained on air that the food journalist Michael Pollan had a tomato named after him and she did not. Joseph Tychonievich heard her lament, got in touch, and offered to breed a new tomato for Kasper.

Tychonievich, now 29, cultivates what he calls “new heirlooms.” That may sound funny, but he defines plants by their qualities, not their age. “It isn’t the fact that they are old that makes heirloom tomatoes so delicious and heirloom dianthus so fragrant,” he says. It is that gardeners focused on things they loved, like taste, and selected their own varieties to save and pass along.

Saving seeds of an old variety and sowing them year after year is one way to protect an heirloom, but Tychonievich crosses the plants himself. “Breeding is looking at different plants and combining their best attributes,” he says, “to get the taste of one tomato with the growth habit or color of another, or to pick out the precise flower for your garden out of a seed packet of mixed colors—customizing plants to your tastes and climate.”

Tychonievich studied plant breeding and genetics at Ohio State and Michigan State universities, and he has been breeding varieties of vegetables, roses, and more. “Gardening has historically been isolating; it is something you do by yourself, in your own space,” he says. “Garden clubs and societies have tried to reach across that isolation, but they cannot compare to blogs, Pinterest, or Facebook groups.” He is quick to say, “The internet made my career.”